The present invention relates to shirred or sheeted strands of tubular food casings and methods of manufacture. More particularly, the present invention relates to sausage or meat casings which are free of residual casing material or loose tab-ends. The improved methods eliminate the need for end-dressing step(s) during manufacturing and avoid filling equipment jamming during stuffing.
Food casings, such as those made of regenerated cellulose and collagen have been widely used for a number of years in processing frankfurters, sausages, bologna, etc. For instance, the basic process for manufacturing small diameter casings of regenerated cellulose is known as the "viscose process" and is described in such patents as U.S. Pat. Nos. 2,999,756 and 3,835,113. Essentially, viscose is extruded onto a fibrous web and regenerated in a coagulating bath to form a tubular casing. The regenerated gel casing is washed, impregnated with a plasticizer, dried and wound into flat reelstock. For convenience in handling and in filling such food casings, they are shirred on high-speed shirring machines, like those described in U.S. Pat. Nos. 2,010,626; 2,583,654; 2,722,714; 2,722,715; 2,723,201 and 3,451,827. In the shirring process, lengths of from 40 to 200 feet of casing are compacted into pleated strands of a few inches, as for example, 4 to 30 inches at a rate of from 10 to 15 ft./sec.
As part of the shirring process, the strands must be severed, for example, from continuous reelstock from which they originated. Most of the methods for severing shirred sausage casings routinely result in the formation of a loose or unshirred tab-like piece of residual casing material which remains at the filling horn insertion (tab) end of the strand. In the case of manual filling of sausage casings the presence of such a loose tab at the horn insertion end can be rectified by hand and does not present a major problem. However, in high-speed, highly automated filling operations the presence of a loose tab-end on the horn insertion end of a strand, can have more major consequences. For example, a loose tab-end can interfere with the proper fitting of a strand onto the stuffing horn of a highspeed filling machine which can become entangled as the horn is inserted automatically into the strand. Under such circumstances, the strand can deshirr from both the filling and horn insertion end causing the process to jam, discharging meat into the filling station work area which means lost meat emulsion, as well as lost production output due to downtime.
Previous efforts to alleviate the problems associated with loose tab-ends have been mainly two-fold. The first approach involves the use of conventional severing means, such as passing a cutting blade or heated wire through the casing. A tab-like end is usually formed on the strand by such cutting methods, which in turn requires further processing step(s) for removal, etc. One representative processing step is described in copending application Ser. No. 559,165, filed Dec. 7, 1983, which relies on an end-dressing made on the strand by ironing down the loose tab-end.
Although use of end-dressings, like that previously described can be effective in alleviating the problems associated with residual casing material remaining on shirred strands, improved methods of severing tubular food casings have been sought which would eliminate the formation of loose tab-ends, all together. This, in effect, would be desirable because it would also avoid the need for end-dressings.
One novel method of severing food casings without formation of loose tab-ends is described in U.S. Pat. No. 3,878,978 and involves impinging liquified carbon dioxide against a food casing until the sidewall becomes brittle from the cold. Force exerted against the brittle film severs the casing without a loose tab-end being formed. Notwithstanding, fracturing the brittle, frozen casing may, in some instances, cause small particles of frozen film to be discharged into the central opening of the casing where they may become entrained in the food product during stuffing. Consequently, the potential hazard associated with this method, in some instances, has detracted from its total acceptability. Accordingly, there is still a need for improved methods of making strands of flexible tubular food casings which are cleanly cut from continuous reelstock wherein the cutting step is performed without developing loose, residual casing material or tab-ends to jam and foul high-speed automated filling equipment.
The present invention provides for a dependable and safe method for severing food casings cleanly and substantially instantaneously without forming loose tab-ends, or requiring special end-dressings. Severing is carried out by means of contacting a thin, high pressure stream of aqueous liquid against the sidewall of the casing. The width and pressure of the stream making contact with the casing are sufficient to sever the casing cleanly and evenly. The severing process does not generate potentially hazardous particles of casing material in the cutting zone which can discharge into the strand. Because the process does not rely on the application of heat in forming an enddressing, casing pleats are not fused, and will completely unfold and deshirr in a normal manner during filling operations. Casing loss or waste is thereby eliminated or minimized and production costs are lowered.
Accordingly, it is a principal object of the present invention to provide the means needed for manufacturing improved food casings without loose tab-ends commonly associated with prior shirring methods.
It is a further object of the present invention to provide means for making sausage casings which are more dependable for use with automated filling equipment.
A still further object of the present invention is the elimination of end-dressing steps in making strands of shirred food casings.
These and other objects, features and advantages of the present invention will become more apparent from the following more detailed descriptions.